Some of the most productive offenses in college football were in the Pac-10 last season, and a lot of the conference's best offensive players -- such as Stanford's Andrew Luck, Oregon's LaMichael James, Arizona's Juron Criner and USC's Matt Barkley-- will be back next season in the expanded Pac-12.

Yet, for many league teams, the key to maintaining a potent offense is rebuilding around -- and in front -- of the outstanding skill-position players.

As spring practice approaches, Oregon and Stanford, both BCS participants in '10, as well as USC and Arizona must address major issues in their offensive lines.

Meanwhile, quarterback competitions and coaching changes highlight the spring outlook for many other conference teams.

Here's a look at the start and end dates for spring drills, as well as a quick look at what each team hopes to accomplish.

Practice begins: March 21
Spring game: April 16
The buzz: Rebuilding the offensive line is Job One. Four new starters are needed up front and at least one redshirt freshman -- maybe several -- need to step in. If the newcomers up front prove they can be effective this spring, Arizona's offense could be among the best in the Pac-12 this fall. Defensively, the Wildcats need two new starting ends and two new safeties.

Practice begins: March 22
Spring game: April 23
The buzz: The Sun Devils must continue to make progress at quarterback. Junior Brock Osweiler started the last two games of 2010, both wins. He'll likely lead the competition to retain that job, but he still has to hold off senior Steven Threet, who was the starter for most of last season. The Sun Devils also need to work on being more physical with their rushing attack.

Practice begins: March 29Spring game: None. Final practice is April 30.
The buzz: Upgrading the play at quarterback is vital. The Bears haven't had stellar play at that position since Aaron Rodgers left. The competition should be interesting among Allan Bridgford, Austin Hinder, Brock Mansion, Beau Sweeney and Zach Maynard, a transfer from Buffalo who sat out last season. Cal also needs to come up with a pecking order at tailback, rebuild its defensive line and find two new starters at linebacker and in the secondary.

Practice begins: March 11
Spring game: April 9
The buzz: Other than adapting to new coach Jon Embree's system, the Buffaloes' top priority is developing cornerbacks. Colorado lost both '10 starters, Jimmy Smith and Jalil Brown, who are expected to be NFL draft picks. The Buffaloes will need sound corners as the move to the Pac-12 and face a list of quarterbacks that include Ohio State's Terrelle Pryor, Stanford's Andrew Luck, Oregon's Darron Thomas, USC's Matt Barkley, Arizona's Nick Foles and Utah's Jordan Wynn. The Buffs need to develop depth at wide receiver.

Practice begins: March 28 or 29
Spring game: April 30
The buzz: The offensive line has to be patched up. Four senior linemen completed their eligibility and left the Ducks with three vacant starting spots in the line. Oregon needs to find effective replacements to maintain its fast-paced, high-scoring offense. The Ducks also are looking for a new go-to receiver to replace Jeff Maehl. There will be five new starters in the defensive front seven, and tackle could be a problem spot.

Practice begins: March 28
Spring game: April 30
The buzz: Finding a capable replacement for departed RB Jacquizz Rodgers is top priority. In addition, graduation and injuries have emaciated the depth along the defensive line. Junior college transfers and unproven prospects will have to emerge there. Coaches also will be looking for more consistency from QB Ryan Katz.

Practice begins: Feb. 21
Spring game: April 9
The buzz: Rebuilding a powerful offensive line that lost three starters is the top priority. C Chase Beeler and G Andrew Phillips had made 68 starts between them. Senior Sam Schwartzstein and sophomore Khalil Wilkes figure to compete at center, with seniors Tyler Mabry and Matt Bentler vying for jobs at tackle and guard along with redshirt freshman T David Yankey and G Cole Underwood. There also needs to be some tweaking done along the defensive line, at linebacker and at cornerback.

Practice begins: TBA
Spring game: TBA
The buzz: The Bruins must develop an offensive identity. New coordinator Mike Johnson faces the task of improving an offensive unit that averaged just 20.1 points per game to rank 104th in the nation last season. The passing attack needs a huge upgrade. The Bruins' pass defense was among the most porous in the country, so major strides must be made in that area. UCLA still doesn't have a defensive coordinator, though.

Practice begins: March 22
Spring game: April 23
The buzz: Finding the right combination along the offensive line tops the list of priorities. The Trojans had significant losses up front and will be looking for junior college transfers, redshirt freshmen and other players with limited experience to demonstrate they're ready to play at a high level. On the defensive side, Chris Galippo and Devon Kennard both need to be on the field, but which one moves from middle linebacker?

Practice begins: March 8
Spring game: April 16
The buzz: The Utes may have to change to a new offensive system. They've run a hybrid version of the spread under coach Kyle Whittingham, but new coordinator Norm Chow prefers a pro-style scheme. Complicating matters, QB Jordan Wynn may miss spring drills with a shoulder injury. The Utes will also have a competition at tailback and at wide receiver. Defensively, the secondary has to be rebuilt.

Practice begins: March 29
Spring game: April 30
The buzz: Identifying a leader at quarterback in the competition between '10 backup Keith Price and redshirt freshman Nick Montana is going to take the spotlight. The Huskies also have to restock at linebacker after losing a lot of talent and experience there.

Practice begins: March 7
Spring game: April 16
The buzz: The Cougars must make improvement along the offensive and defensive lines. They allowed 51 sacks in 2010, the second-highest total in the nation. The rushing attack was stuck in neutral, too. Meanwhile, the Cougars' defense was among the nation's worst against the run and accumulated just 23 sacks. Coaches need some playmakers to emerge on that side of the ball.

Olin Buchanan is the senior college football writer for Rivals.com. He can be reached at olin@rivals.com.